题目内容
用自己喜欢的方法计算.
(1)1.73+1.73×3.5+5.5×1.73
(2)3.5×[(1-0.05)÷1.9]
(3)68×0.11+8.9×6.8
(4)8.88÷3.7×1.25.
解:(1)1.73+1.73×3.5+5.5×1.73,
=(1+3.5+5.5)×1.73,
=10×1.73,
=17.3;
(2)3.5×[(1-0.05)÷1.9],
=3.5×[0.95÷1.9],
=35×0.5,
=17.5;
(3)68×0.11+8.9×6.8,
=6.8×1.1+8.9×6.8,
=6.8×(1.1+8.9),
=6.8×10,
=68;
(4)8.88÷3.7×1.25,
=8.88×1.25÷3.7,
=(8+0.8+0.08)×1.25÷3.7,
=(8×1.25+0.8×1.25+0.08×1.25)÷3.7,
=(10+1+0.1)÷3.7,
=11.1÷3.7,
=3.
分析:(1)运用乘法分配律简算;
(2)先算小括号内的,再算中括号内的,最后算括号外的;
(3)原式变为6.8×1.1+8.9×6.8,运用乘法分配律简算;
(4)此题属于同级运算,可先算乘法,再算除法.
点评:此题考查了小数的四则混合运算,注意运算顺序和运算法则,灵活运用所学的运算律简便计算.
=(1+3.5+5.5)×1.73,
=10×1.73,
=17.3;
(2)3.5×[(1-0.05)÷1.9],
=3.5×[0.95÷1.9],
=35×0.5,
=17.5;
(3)68×0.11+8.9×6.8,
=6.8×1.1+8.9×6.8,
=6.8×(1.1+8.9),
=6.8×10,
=68;
(4)8.88÷3.7×1.25,
=8.88×1.25÷3.7,
=(8+0.8+0.08)×1.25÷3.7,
=(8×1.25+0.8×1.25+0.08×1.25)÷3.7,
=(10+1+0.1)÷3.7,
=11.1÷3.7,
=3.
分析:(1)运用乘法分配律简算;
(2)先算小括号内的,再算中括号内的,最后算括号外的;
(3)原式变为6.8×1.1+8.9×6.8,运用乘法分配律简算;
(4)此题属于同级运算,可先算乘法,再算除法.
点评:此题考查了小数的四则混合运算,注意运算顺序和运算法则,灵活运用所学的运算律简便计算.
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